Sound quality can be defined as the physical pleasure or fatigue experienced by a listener and is typically characterized in a live setting by the skill of musicians, tonal quality of their musical instruments and the physical traits of the venue. Related to effecting sound quality, architectural acoustics is the science of controlling sound within buildings and can be broken into four general areas: (1) analysis of the exterior envelope of the building; (2) analysis of noise transmission from one building space to another; (3) analysis of the surfaces of interior spaces of the building; and (4) analysis of mechanical equipment noise generated within the building. Motor vehicles, military vehicles, aircraft and the like can use a similar approach by analyzing the exterior envelope of the vehicle, the noise transmitted from one space of the vehicle to another space, the characteristics of the surfaces of the interior spaces of the vehicle and noise generated by mechanical equipment of the vehicle. However, a motor vehicle, military vehicle, aircraft and the like has an additional complication of having a mobile interior space that is exposed to a wide range of noise scenarios, some changing within a given trip, mission and/or ride in the vehicle.
Looking particularly at the interior space within such vehicles, one method to control sound therein is to use fabric to cover interior surfaces in order to absorb the sound. However, fabric surfaces can be difficult to clean and it can be desirable for a surface to reflect sound rather than absorb it. Therefore, a panel or a surface on a panel that can change or alter its acoustic characteristics as a function of time, noise scenario and/or occupant instruction would be desirable.